<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script src="../js/vue.js"></script>
    <div id ="app">
        <p>First name:<input type="text" v-model="firstname"></p>
        <p>Last name:<input type="text" v-model="lastname"></p>
        <p>fullname:{{fullname}}</p>
        <button @click="change">改变fullname</button>
    </div>
    <script>
        let app = new Vue({
            el:"#app",
            data:{ 
                firstname:'',
                lastname:''
            },
            methods:{
                change(){
                    this.fullname='Harry Potter';
                }
            },
            computed:{
                fullname:{
                    get:function(){
                        return this.firstname+''+this.lastname;
                    },
                    set:function(newVal){
                        var arr = newVal.split('');
                        this.firstname = arr[0];
                        this.lastname = arr[1];
                    }
                }
            }
        })
    </script>
</body>
</html>